Platen press



Sept' 5, 1939 R. w. STANLEY E-r AL 2,172,003

P LATEN PRESS med May 2o, 1957 s sheets-sheet 1 R. w. STANLEY Er A1.2,172,003

Sept. 5, 1939.

' PLATEN PRESS Filed May 2o, 1937 3 Sheets-Sheet 2 T P- f1 E E I I T 1`Sept 5, 1939- R. w. STANLEY ET Al. v 2,172,003

PLATEN PREss Filed May 20, 1937 3 Sheets-Sheet 3 Patented Sept. 5, `1939PATENT- MOFFICE PLA'rEN PRESS Richard W. JStanley and Ericsson Il.Merrlt Lockport, N. Y.,' assignors to Merritt Engineering and Sales Co.,Inc., Lockport, N.

poration of New York Application May 20, 1937, Serial No. 143,734 Y 2Claims. (Cl. 144-281) The present invention relates to presses, and moreparticularly an improved single or multiple opening hot plate press forthe manufacture of plywood' and similar products requiring the 5simultaneous applicationv of heat and pressure to sheet materials.

4The principal objective is to provide a new form of hot plate press inwhich sheets of veneer,

or lumber .cores and/ face veneer, may be adhesively united by heat andpressure with a new degree of uniformity of treatment, the design beingsuch'also that thehmachine can operate at greatly increased speedA andwith proportion*- ately increased output. 1 Obviously this press '1B maybelused for performing vany voperation in.

which a rapidl application of pressure, or heat .'and pressure isdesirable. This press may of cours'ex also be used with unheated platesif desired. The present improved construction for securing these resultsalso obtains a variety of otherincidental advantages the nature of which`will be readily understood from the subsequent detaileddescription ofthe machine.

To the accomplishment of the foregoing andl related ends, the invention,then comprises the features hereinafter fully described, and par'ticularly pointed out in the claims, the followdescription setting forthin detail certain illustrative embodiments of the invention, thesebeingindicative however, of. but a few of the various ways, in which theprinciple of the invention may be employed. `In presses of thischaracter the custom for tle most'part; is to so design the press thatthe ad load is also the means for opening and closing the press. ,Inthe. present design the respective functions of opening and closing andthat of pressing have been divorced from each other withl an appropriateprovision of separate mechanical means for performing these two distinctfunctions. In the present construction ,openind and closing isaccomplished by mechanical means, whilevthe application of working pr rewhich follows closing, is accomplislied byJiluid pressure applied eitherby hy draulic means but preferably applied by pneumatic means.` l

The present application supplements. two

' a previous applications, ser. No. 744,132, E. H.

Merritt,.now issued as Patent No. 2,148,704, dated February 28,;1939.and Ser. No. 118,505, RaW. Stanley, rthe present construction beingadevelopment based in part` upon `the earlier disclosures, Thesepriorapplications. described the means for' applying the working pressure tothe use of a diaphragm pressure element which is also used in thepresent construction, The features of balancing the weight of the movingparts and of differential movement of the plates in an accordion-likeaction, are new elements 5 with which the present application isconcerned, In the earlier applications also, the operation of thediaphragm was by means of a liquid only,

'while in the present design the improvement has been added optionallyoperating 4the diaphragm lilr by the elastic medium 'of air or a gas,this feature cooperating with the accordion'movement. lI n addition tothe mechanical features and combinations. of machine elements comprisingthe present hot plate press construction, the 15 various new featuresand functions provided thereby, afford a means for the operation of anew process and treatment in laminating panels and plywood. This newprocess forms the subject of a separate application filed simulta- 2oneously with the present. case.

In the annexed drawings l Fig. 1 is a side elevational view of anembbdiment of the invention; Fig. 2 is a diagrammatic plan view' thereofshowing the arrange- 25 ment of the gearing on the top of the press;Fig. 3 is an end elevation .of the construction shown in Fig. 1;' Fig;44 is an enlarged sectional detail of the gear-driven nut; Fig. 5 is adiagrammatic elevational view illustrating the se- 30 quence of pick-upin the closing of a platen press of usual form; Fig. 6 is a similarshowing of the pick-up by a press in accordance with the pres-v entinvention, and Fig. -7 is a transverse crosssectional view of the press,taken on the line lpassing through the heady B are threaded for aconsiderable distance and engage nuts F mounted on the head such thatwhen turned theycause the head to -move up or downv lon the threadedrods.- .As seen in Flg. 4, this mgunting' 50 may comprise a bushing F1secured to the head,

and. enclosing a rotatable sleeve `F2 -whose upper end is provided withgear teeth Fa, and is secured by suitable means to4 the screw threadednut portion kF4 which turns on the. threaded rod. 55

4The toothed portionsFa, constituting pinions,

ing, such as F7, Fa, Fo. F1o from a motor m conveniently located on thepress-head. Rotation of the motor shaft, thus through the gearing Ffa toFs rotates the nuts Fin appropriatediretion. I

as desired, depending upon whether the press is to be closed or -is tobe opened.

.If this machine were to, operate as a conventional screw press the basewould restdirectly upon the foundationv and power means would beprovided adequate notV only to close the press but to exert the requiredmaximum pressure upon the' work. However, in 'the present invention, the

screw press action is limited in its function to theJ mere work 'ofbringing the plates into mutual ',contact, while working pressure issupplied subsequently by separate means, preferably, for emample, by`avdiaphragm as described in said 'pending' applications, Ser. No. 744,132now issued hndSer. No. 118,505.

as Patent N0. 2,148,704, dated February 28', 1939,

Since one of the principal objects of the present -inventio'n is tofacilitate using maximum open?,

ing and closing speed, means have been provided for balancing the weightofthe necessarily m -L sive and heavy moving parts against each, other.The head weight'ls balanced against the weight of the base and strainrods, and half ther-plates 'are also balanced against 'the other half.To acf` complish this the'base A does not restupo'n the foundation butis suspended in very much the same manner as a scale platform. Thefoundation members carrying the entire weight of the press are twonon-revolving shafts G, one at each end of thepress, and theends of eachshaft are keyed to blocks H which, in turn, are bolted to thefoundation', which may be of concrete for example.

. Upon each shaft are mounted two spaced rocker arms I carrying pivot'pins J, equally spaced on "opposite sides of' its center. The pivotpins in the inwardly-extending ends of the rocker arms carry rollers Kwhich bear above and below on shoulders In on thebase. These-shouldersare faced with hardenedsteel plates to reduce wear. Th pivot pins intheoutwardly-extending ends of the rocker arms. carry 'connecting' arms Mpivoted likewise attheir upper ends in ears N welded or otherwisesecured to the head B.

`Disregarding for the moment thethreaded nut connection 'of the hea`d tothe strain rods, it is eeen that the weigh#l of the together with:

the eaghed strain rods, 1s carried by the rollers operating elements, istransmittedl through the connecting rods M tothe pivot pins in' theouter endspf the rocker arms I. =Thus, if it'is`assumed that the weightof the baseA and head are equal they are in balance with each other. Toinsure equality, the head', which 1s naturally someehat' lig/liter` glueto the strain rods being carried'l by the base,\is provided 'with ahollow space into, which can be poured suiiicient concrete -to equalizethe weightwith the base.C However, because ofthe threaded connection ofthe strain rods to K, while the weightf the head, together with itspleted. -f

Consequentlywhen the nuts F- are revolved in a direction to cause thehead to descend on the rods C, the connecting rods M depress-the rocierarms I at their outer ends and raise the rollers K pivotedtto 'theirinner ends. Therefore, as the head descends the base ascends an equaldisftance and at the same speed, and although the head and the base aremoving in opposite direcrtions they are moving inI balance.

The result of thisrelationship is thatsince head and base are jxnovingat the same time in "opposite directions toward a common middle point,the time of :closing has been reduced by one half without havingincreased the rate of .travel of the head or Abasernembers beyond thatcommonly used in a press wherein only one of i movement of Vthese*massive parts yis-their inertia, and the very desirable result has beenattained Aof reducing the power required to open and close these memberstravel. Furthermorel since head y and base are balanced the onlylimitation to quick i the press to thelowest termswith a simultaneous s50 pei` cent decrease in the time interval required for the openingandclosing movement. y -In,.the conventional type 'of hot presstheplates' are suspended from the press? head,/ usually byv Ahanger. rodsin such -a way that when the press is open there is an equalopergingbetween each pair ci adjacent plates. This open space or daylight;

as'it is commonly called, ordinarily'varies 'from one to four inchesaccording tothe kind of work the press is designed to handle. If in thepress` here shown, the plates werehung from the head inf the usualmanner and the pressV wasclosed from below by the upward movement of aram `which raised the base towards the head, the closing up'of thedaylight spaces would be a suc'- lcessive movement starting with thelowest space Y and ending with the uppermost one. The base,

, v :1 -.v In contrastto such type of closing, the #resent inventioninvolves adiilere'ntial closing movement shown. I

1n other words, would ummetehf plea-.up en diej@ asis illustrated byFig. 6.v In this'difierentiai movement it will be seen that all theplates are in motion from beginning to end, thatf'allf spaces begin toclose at the same time, are alhnally closed at the same instant',-andare at ,alltimes open to the same extent before closing is comReferringto the and 2, it is seen Vthat the strain rodsC at op-r positeends of the. press vare rigidly connected at, lthe )ipper end byA a yokel. Mounted in these yokes are two shafts-2. Thus the upperen'ds press`assembly as ir Figs. i 55 of the strain rods are held'together inai'iframe-oo Y in much the same way as they l are held together .at4,their lower ends by the base. The strain rods.

jtherefore, can act as rigid guides for movementsi of the head. Ateaclhend of the press a'painof arms 13 is keyed to shafts 2, and thereare con-- 05 nectingl rods 4` with pivots at [which connect their outerextremities with-ears l'bonded to the Y.

' head B. At equal intervals along the arm 3 be-` 'tween the shaft .z,endtheoonneouhg rod pivot 8 are attached hanger rods i of varyinglength, 7o

each plate in the press being Ystampi-ted by a group of four of theserods all ofen equal length which iis adjusted to provide the desiredspacing or maximum'daylight between the Aplates when pansion orcontraction of the diaphragm. Thispivot connection with the arm 3 isprovided with a coil spring 'l to provide a cushion for taking up anyinequalities in the thickness of the panel assemblies in the severalopenings and thus avoid Vaccidental stresses which otherwise might.cause breakage.

The arms 3 are shown at the middle point of v stationary the rockingmovement of arm 3 wouldv cause the plate hanger rods 6 to movevertically various distances depending upon -the distance veach rod ispivoted from the center of shaft 2. 'I'his in turn would cause theplates toV move vertically variousv distances depending'upon theposition of the point of attachment of their particular hanger rods. Thelowesthung plate would be supported by rods pivoted farthest from shafts2 and would move the greatest distance, while the top hung platesupported by rods pivoted closest to the shaft 2 would travel-the leastdistance. However, yoke l is not stationary since it is attached to thestrain rods, which, in turn, are attached -to the movable. base. It isseen that when the head descends the base ascends and carries the yokesI and shafts 2 with it. The arm 3 atthe middle point of its length istherefore a dead center and one end of the arm moves up wh'ile the otherendA moves down anequal distance. Transferring this movement of'the arms3 to the plates in the press, the movement'is'likewise towards a'neutral center point, the topmost plate moving downward and the bottomplate moving upward while the middle plate in the group remainsstationary shown in Fig. 6 at center line XY.

In connection with the foregoing description of theA means for givingthe plates an accordion movement during the opening and closing, it isparticularly pointed out that the maximum opening between the plates isadjustable at will since it depends on the amount of movement of headandbase, which can be limited at any.; desired travel short of the fullmovement. If the maximum space or daylight between the plates is threeinches when head and base are separated the' maximum` distance from-each other, the space`between the plates will be `one and one-'half'inches when head and'base are at .the middlepoint of their approach.Under operating conditions if it is assumed that the thickness of panelsto be pressed runs fromv one-sixteenth of an inch to two inches, it isobvious that a `maximum opening' of Athree inches between plates is notn.1--v ways necessary. Obviously also it is needless to provide morethanabout a one-inch opening when operating on panels onlyone-sixteenth.

vinch thick. Therefore it is desirable to limit the movement of head andbase in conformityv with4 the space requirement as regards opening forthe work in hand. This preventsv unnecessary travel in opening andclosing and saves both time 'and power. With the present design thisadjustment of the daylight spaces to thework in hand becomes merely amatter of stopping the actuating motor at the right time. Automaticmeans for accomplishing this will be described later.

' For applyingworking'pressure after the press is 'closed by, mechanicalmeans.` use" lsmade ofV diaphragm d incorporated `in a, retainer-"withla. cover lfree to move up and downwithfthe exfis shown and `describedin our co-pending applications 744,132'and 118,505. In-the press hereshown the expansion medium in the diaphragm may be either air oraliquid. One purpose ofv the press design here shown is as alreadystated to secure the maximum speed of opening and closing, hencepneumatic means for applying the operating pressure is preferred.Increased speed of movement means increased shock when the plates cometogether on the panels lying in the open spaces. 1n co-pndingapplication Ser. No. 118,505 provision is described for introducing asmall amount of liquid in the diaphragm` just before the platescompletelyclose u'pon the panels. The purpose of this is to facilitatethe opening of the press. When the press is pneumatically operated, theintroduction of a small' amount of air in the diaphragm performs thisfunction as well as an additional one.

vAir is' elastic and compressiblewhile liquids are rigid andincompressible. Consequently air in the diaphragm as compared to liquid,converts the latter into a cushion which absorbs and dissipates shockoccurringwhen the plates make vcontact at the end of a relatively rapidclosing movement. Furthermore, compressed air isa quick acting medium,and its isecooperates with and supplements quick opening and closingmovement by providing also quick application and withdrawal of highworking pressure. To this must also be added the advantage derived fromthe cushioning effect of the pneumaticshock absorber permitting the useof high closing speed.-

While a diaphragm'andparticularly a pneumatic diaphragm, is preferred asa means of applying working pressure, the use of other pres-` sure meansis not excluded. With the balanced A- accordion movement of the pressplates which provides for simultaneous closingof the various openingswith the head and base both approaching a commoncentre and while themoving parts involved are maintained in a condition of balance, it isobvious that manyv advantages will "be secured with almost any apparatus`for applying Aworking pressure. For example with a hydraulic ram, onlyworking pressure has to be applied by the ram and consequently onlyslight 'ram movement is needed permitting quick pressing. However, thislacks the very desirable cushioning effect supplied by .the pneumaticdiaphragm. Y

y.To co-relate'the mechanical opening and closing with high.pressur'epneumaticfor hydraulic operation, automatic electric stops andcontrols are desirably provided, essentially the same as showninca-pending application Ser. No. 118,505,l

and notdrequiring detailed showing here. l

In operation, the cycle starts'withthe press open, the amount `ofdaylight between plates having been determined by the thickness ofpanels to be pressed, and the automatic stop having been set todiscontinue the opening movement atthe end of eachcycle after thepredetermined amount of travel has occurred. The

panel assemblies are loaded into .the individual.

press openings, either singly or simultaneously by a loading device,whereupon the operator presses a control button which venergizes themotor and 'causes revolution ofv the nuts', which bring the' base andhead towardseach other until the spaces are fully-closed. 'Just beforethe instant when the motorl is automaticallyfcut out and the closingmovement ends, the air valve 1S' animatie@ were@ by' decirle @mm1-.1 i5

aimons and a .small 'amount of 'admitted to the tion of. final pressure,but also assures an easy diaphragm'which becomes partly iniiated andacts as a cushionto take up the shock ofmechanand even shockless.contact when nal pressure is applied.

ical closing. Almost instantly thereafter full The use of mechanicalmeans for opening and 5 working pneumatic ,pressure `is built up withinclosing is fast as compared to hydraulic means 5 the diaphragm, and thepanels are then kept and,- furthermore, requires lesspower to operate.A

A4under-A pressure until theaactind of the heat in Balancing theV weightof .the heavy massive the plates has set up the adhesive and the members-in motion reduces the power cpu.-

bondingis inished.4 If the pressing is repetition sumption. l l0manufacture-of the same umts so-that the same f Movement of balancedweight contributes to' lo press-timers repeated with each press load,autohigher closing speed. l m'atic means -rnay be provided for timing,press- Since the means employed` to balance weight i ing, and startingthe opening cycle, or at the involves simultaneous movement of the headand end of the pressing the operator may press ag`base towardseach'other, the distance traveled by push button which closes the airvalve and opens eacl and the-time consumed in closing is cut in 15 L theexhaust. Y As soon as the diaphragm isdehalf. This is aurther importantcontribution l 'ilated the motor is energized and the press is toclosing speed -A opened 'bythel mechanical movements actuated Movementof balanced moving members-reby the motor. The plates Vreturn to` theirorigduces wear and tear and increases the life of the inal position atwhich the pre-determined day- `press. .v y l 2o' -lightis againprovided. l y J Theaccordion movement, by providing simuleA Eromtheconstruction and operation of the taneous contraction of the pressfopeningsl terimproved press it will be particularly noticed minatingin` simultaneous pressure contact, prothat some of the maior advantagessecured byf vides an advantageous means of adjusting the 25the'invention are as follows: n daylight to the' thickness; of thepanels to be 25 Hot pgesses are relatively costly machines and pressed.Thisveliminatesunnecessary travel and l must attain 'maximum output tojustify them'- the waste of opening and closing time in such selvespeedin opening and closing. is a'majoi; idle movement, This, in turn,increases producfeature'in production. Any reduction in the rel- Yr`tionand provides a further gain in aquicker 'atively idle time consumed inclosing and-openapplication of 'bondingxpressura which assists in 30ing, as in the present invention, increases the vavoidinginjury to the`heat sensitive adhesive. number of pressings per hour or .per day. Whereall the spaces begin to open up at the Heat beginsto act upon anadhesive as soon same time and at the .same rate, the unloading as itpenetrates to the glue line.v If the heatof the press can begin themoment the panels are 3 5, reaction prficeedsfar before the applicationorA released from pressure, 'and in turn, reloading 35 full bondingpressure, the bond is .either absent can start before the spaces arefully opened and or-inferior. is especially true with`r recently cancontinue after the spaces begin to close. This developed quick settingadhesives. .The quick is a' further economy in the timecycle requiredclosing 'features of this` press design avoids this for` each pressing.40 defect. `vWhile movement ofthe heavy members of the 40 To obtain eaproduct which is both uniform press has been speeded up by balancing theand o'rf ythe highest 'quality it is essential that weight, and whilevthe time of opening and clostheY panels in all Ispaces ofa hot pressreceive ing has been .halved by moving headand base identical and idealheat and pressure treatment. simultaneously, the rate of closing theindividual The present invention provides this uniformity openings has.'been greatly slowed down. Thisd because all press openings begin toclose at the seeming paradox is explained as follows: If in a. f sameinstant and close uniformly and simulve opening press panels one halfinch thick areA taneously at the same rate. This is the result beingtreated the 'space should be about one and'. of `the diierential closingmovement and is an pne half inches in height if one inch of space isimportant advance over the conditions which V'provided above: each panelior-ease in entering sa prevail in a press havingthe priorfart. progres-'into the press. 4It would then require a movement sive closing movementIn the latter, a panel/ of five inches to close all five spaces; Thehead lying -`in vthe opening 'that ,closes rst, receives would traveltwo and one half `inches, and the thevweight of the plate above it andis in conbase two and oneA half inches. Since all spacesl tact with thehot plates throughout bcthof its close together andsince each space tobe closed is 55 surfaces, but the mechanical pressure is' only one inch,the space closing rate compared with f very low` and consequentlytheheat quickly peni the head and base -rate of movementisas one is'eilates t0 the glue line from the plates causing to two andv one halfor as two'is to `five.' The tha adhesive tQ'begn t0 reat in the absne 0fplates vin closing, approach eachother; at only blinding Prissura fstinWithut bonding Pres' two fthsthe'sped of the head and base move- 00 surethe Wegtof s cssi've plates is' Sided as ment. .In other words theplatesNconie together uccessive. @m5 above thmtom one alfein the sameelapsed time as the head andl base, closed up' Thus with pmgrssiveclosing great. liitthe latter travels two and one halftimes as y inqxaliw exists as regards the heat treatment f r nd tw d o ihan times sfast .ums a of theadhsive in the panels obtained from the'- a Q anne e5`several openigs. A'further objection vlies in vel? gentle and 510W clmof the ind-mdlal ai". have been obtained notwithstanding the V stheshocks orybumps receiied by the panels in spa-'ces 1 K t i. thelowenspaces as eaclr space vis closed andthe greainicease'm @tal .closinSpee@ f the prss' piate'n'ext above it picked up. Awith any nigh The useOfeadaphrasm' a Separate means -m closingspeed-vthese bumpsact toniompresis` the for applylngkworking pressure vhas advantages 70 d woodailectinfthe final thickness of the 'iin-,f -fullyset forthinco-pending'applications. butaishe'ci'pan'elsr and thefaihesiveislalsodisturbed i'l'lrther advantage ,has lbeen secured by sub' midi-3D1the-s'm'ieet -Th Qn-Stl'llcf stitutingainfor liquid as the pressureinstrument tion -here-4 escribed not only eliminates these .inthediphragm. lThe speed at'which air builds i 'vs -{bumpsor beforetheapplica- ,upoperatih'g pressure as comparedrto liquids I5 u I r l scontributes to speed of operation and consequent increased output. I

A further advantage is the shock absorbing cushioning eifect of the airas. compared to liquid ,in absorbing the shockl of closing on thepanels.

'I'his both relieves the mechanism of Wear and tear and makes greaterclosing speed permissible;

Other modes of applying the'prnciple of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claims, or

plywood, upperv and lower press-heads, a series for each` plate, andarms swingably mounted on ythe equivalent of such, be employed. Wetherefore particularly point out and distinctly claim as our invention:

1. In a platen press'` adapted for laminating of plates therebetween,"and means ,for movably supporting 'said plates, including hanger 'rods2. In a platen press adapted for laminating 5 plywood, upper and lowerpress-heads, a series of plates therebetween, and means for movablysupporting said plates, including hanger rods for eachl plate and armsswingably mounted on the 10 upper press-head `forA arcuate movement in avertical plane, the upper ends of said plate hanger rods being carriedby said arms, take-up springs interposed between the upper ends of saidplate hanger rods "and said arms, and means for 15- arcuately movingsaid arms in relation with the press-head movement. y

j RICHARD W. STANLEY.

ERICSSON H. MERRITT.

